Head assembly and storage device

ABSTRACT

A head assembly for an information storage device that includes a head slider with a read/write element for reading/recording information to/from a disk and a suspension for supporting the head slider. The suspension includes a generally planar sheet that extends in a longitudinal direction from a first end to second end and an arm attaching portion located near the first end of the generally planar sheet of said suspension. The arm attaching portion is adapted to be attached to a head arm. The suspension also includes a slider attaching portion positioned near the second end of the generally planar sheet of the suspension, where the slider attaching portion extends generally in the longitudinal direction and is surrounded by a generally U-shaped opening in the generally planar sheet. The slider attaching portion faces a securing surface of the head slider. At least one of the slider attaching portion of the suspension and the securing surface of the head slider includes a nonplanar portion, and the head slider and the suspension are affixed to each other at the nonplanar portion, whereby the effects of torsion upon the alignment of the head slider are mitigated by the nonplanar portion. Preferably, the nonplanar portion includes a curved portion.

[0001] The present invention relates to a head assembly for readingand/or writing information, which has a head slider positioned at apredetermined position with respect to a storage medium, and it alsorelates to storage devices such as magnetic disk devices (floppy diskdevices, hard disk devices, etc.), optical disk devices and tape diskdevices.

BACKGROUND OF THE INVENTION

[0002] The conventional storage device is constructed to rotate a diskso that a head slider is caused to float a small distance from thesurface of the disk, enabling the head slider to move in the radialdirection of the disk. This conventional head slider is generallyprovided with a head element for recording and/or reading information.

[0003] In current information storage devices using magnetoopticaldisks, the head slider has a magnetic head for reading and/or writing abias magnetic field to/from the head slider. In addition, an opticalhead of an objective lens or luminous elements for leading the light tothe disk can also be mounted upon the head slider.

[0004] Most types of head sliders are supported by suspensions havingelasticity which allows for flexing of the head slider towards or awayfrom the disk. The head slider floats a slight distance from the surfaceof the disk due to the action caused by the air flow generated on therotating disk surface, i.e., the head floats due to the principles ofdynamic air pressure bearings. Higher recording densities and increasingminiaturization are currently being achieved with disk devices, and headsliders are being designed for lower floating heights to achieveminiaturization and lighter weight. However, if the floating height ofthe slider is designed so that it is too low, the head slider comes intocontact with the disk surface due to floating level fluctuations. Such acondition has not been a problem in the past, but eventually, theprobability of the slider coming into contact with the disk will be toohigh, and reliability will reduced because of damage occurring to thehead slider and/or the head element parts.

[0005]FIG. 1(A) shows a prior art head assembly. The head assembly 20 isgenerally composed of a head slider 26 and a suspension 21. Thesuspension 21 is formed by press punching one sheet of an SUS plate, andhas an arm attaching surface 23 which is to be attached to an arm of thedisk device. The arm attaching surface 23 is formed with an attachinghole 23A, and is furnished with a spacer 23B to ensure that theattaching strength is adequate.

[0006] The suspension 21 is also provided with a slider attachingportion 25D for attaching the head slider 26 to the suspension 21 at theopposite end of the arm attaching surface 23. The adhesion surface 26Tof the head slider 26 is firmly secured to the suspension 21 by means ofan adhesive 22 coated on the slider attaching portion 25D. The sliderattaching portion 25D is created by a generally U-shaped hole 25 formedaround the perimeter thereof, and the slider attaching portion 25D issupported by three connected beams 25A, 25B, 25C.

[0007] The structure of this suspension 21 enables the head slider 26 tobe responsive to the air flowing backwards, forwards, to the right, andto the left. However, since the suspension 21 is, as stated above,press-formed, it is often twisted in direction “a” or in direction “b”due to stresses created during forming. The slider attaching portion 25Dis, accordingly, affected by the twisting, though the arm attachingsurface 23 of the disk device is designed to be positioned so that it isparallel to the disc surface. Furthermore, since the slider attachingportion 25D and the adhesion surface 26T of the head slider are planar,if the head slider 26 is attached to a twisted slider attaching portion25D, the head slider 26 will be inclined with respect to the disksurface.

[0008] In summary, when the slider attaching portion 25D is twisted atan angle of α/2 in direction “a” with respect to the attaching surface23, the surface 26D of the head slider 26 facing the disk (in this casethe lower surface of the slider) is inclined similar to plane 29A ofFIG. 1(A). Thus, because of this inclination, there is a reduction inthe floating height of the read/write element 26A (which may be any typeof element for reading and/or writing information to/from a disk).Additionally, the frequency of contact of the slider with the disk isalso increased. These conditions often result in damage to the head, thesuspension and/or the disk.

[0009] Conversely, when the slider attaching surface 25D is twisted atan angle of α/2 in direction “b” with respect to the attaching surface23, the surface 26D of the head slider 26 facing the disk is inclined ina manner similar to plane 29B. Thus, the floating height of theread/write element 26A is increased, and the distance between the headand the recording film of the disk is increased so that the recordingand/or reading characteristics are degraded.

[0010]FIG. 1(B) shows a graph of the floating height of the head slider20 along different portions of radius of the disk. Line 41 representsthe case with no torsion existing in the suspension, and the floatingheight is constant from the inner side of the disk to the outer side andwhere the head slider floats at a predetermined height, irrespective ofits position on the disk. Line 42 represents the case with torsionexisting in the suspension, and where the floating height is reducedgoing from the inner side of the disk to the outer side, resulting ininstability. Since the floating height of the head slider is lower thanthe designed value, the probability of the head slider coming intocontact with the disk is increased. Thus, to secure the floatingstability of the head slider, there should be no torsion in thesuspension.

[0011] Accordingly, in view of the problems discussed above, anobjective of the present invention is to provide a head assembly and astorage device which are capable of improving the floating stability ofthe head slider, as well as improving the reliability of the storagedevice. It is another objective of the invention to provide a headassembly and a storage device which can provide a highly preciseparallel relationship between the surface of the head slider facing astorage medium and the attaching surface of the support plate at thedisk device side.

BRIEF SUMMARY OF THE INVENTION

[0012] Briefly, with head assembly of the present invention, it ispossible to arrange the surface of the head slider facing the disk to beparallel to the disk surface, even if there is some torsion or twistingin the suspension. The effects of torsion can be mitigated against byusing a nonplanar or curved portion, on the suspension, for attachingthe slider to the suspension. Alternatively, it is also possible tomitigate the effects of torsion by using a nonplanar or curved portionon the surface of the slider where it is attached to the suspension. Asan additional alternative, it is also possible to have nonplanar orcurved portions on both the suspension and the slider attaching surface.As a result of the nonplanar surface(s), the read/write element will beheld at a predetermined distance from the recording film of the disk.Thus, the floating height of the head slider can be held at a constantdistance from both the inner and outer sides of the disk. Accordingly,it is possible to enhance the recording and reading efficiency,durability, and reliability of the disk device by reducing the frequencyof contact between the head slider and the disk.

[0013] More specifically, the present invention relates to a headassembly that includes a head slider with a read/write element forreading/recording information to/from a disk and a suspension forsupporting the head slider. The suspension includes a generally planarsheet that extends in a longitudinal direction from a first end tosecond end and an arm attaching portion located near the first end ofthe generally planar sheet of said suspension. The arm attaching portionis adapted to be attached to a head arm. The suspension also includes aslider attaching portion positioned near the second end of the generallyplanar sheet of the suspension, where the slider attaching portionextends generally in the longitudinal direction and is surrounded by agenerally U-shaped opening in the generally planar sheet. The sliderattaching portion faces a securing surface of the head slider. At leastone of the slider attaching portion of the suspension and the securingsurface of the head slider includes a nonplanar portion, and the headslider and the suspension are affixed to each other at the nonplanarportion, whereby the effects of torsion upon the alignment of the headslider are mitigated by the nonplanar portion. Preferably, the nonplanarportion includes a curved portion.

[0014] The present invention also relates to an information storagedevice incorporating the above-mentioned head assembly, as well as tothe suspension of that head assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Preferred embodiments of the present invention are describedherein with reference to the drawings wherein:

[0016]FIG. 1(A) shows perspective view of a prior art head assembly;

[0017]FIG. 1(B) shows a graph of the floating height of the head sliderwhen positioned in different radial locations on the disk;

[0018]FIG. 2 shows a disk device of the first embodiment of the presentinvention;

[0019]FIG. 3(A) shows a perspective view of the head assembly of thefirst embodiment of the present invention;

[0020]FIG. 3(B) shows an enlargement of part of FIG. 3(A);

[0021]FIG. 3(C) shows a modification of the first embodiment in a viewsimilar to that of FIG. 3(B);

[0022]FIG. 4(A) shows a perspective view of the head assembly of thesecond embodiment of the present invention;

[0023]FIG. 4(B) shows an enlargement of part of FIG. 4(A);

[0024]FIG. 5(A) shows a perspective view of the head assembly of thethird embodiment of the present invention;

[0025]FIG. 5(B) shows an enlargement of part of FIG. 4(A);

[0026]FIG. 5(C) shows a graph of the floating height of the head sliderat different radial portions on the disk;

[0027]FIG. 6(A) shows a perspective view of the head assembly of thefourth embodiment of the present invention;

[0028]FIG. 6(B) shows an enlargement of part of FIG. 6(A);.

[0029]FIG. 7(A) shows a perspective view of the head assembly of thefifth embodiment of the present invention;

[0030]FIG. 7(B) shows an enlargement of part of FIG. 7(A);

[0031]FIG. 8(A) shows a perspective view of the head assembly of thesixth embodiment of the present invention;

[0032]FIG. 8(B) shows an enlargement of part of FIG. 8(A);

[0033]FIG. 9(A) shows a perspective view of the head assembly of theseventh embodiment of the present invention;

[0034]FIG. 9(B) shows an enlargement of part of FIG. 8(A);

[0035]FIG. 10 shows a perspective view of the head assembly of theeighth embodiment of the present invention;

[0036]FIG. 10(B) shows an enlargement of part of FIG. 10(A);

[0037] FIGS. 11(A) through 11(D) show views of the steps of the adhesionprocedure of the head slider of the first embodiment;

[0038] FIGS. 12(A) through 12(E) show views of steps of the adhesionprocedure of the head slider of the second embodiment;

[0039] FIGS. 13(A) through 13(E) show views of the steps of the adhesionprocedure of the head slider of the third embodiment;

[0040] FIGS. 14(A) through 14(D) show views of the steps of the adhesionprocedure of the head slider of the fourth embodiment;

[0041] FIGS. 15(A) through 15(D) show views of the steps of the adhesionprocedure of the head slider of the fifth embodiment; and

[0042] FIGS. 16(A) through 16(B) show views of the steps of the adhesionprocedure of the head slider of the sixth embodiment.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0043]FIG. 2 shows a magnetic device which is an information storagedevice of the first embodiment. The magnetic device includes a drivebase 28 for creating a housing space within the device and a cover 18.The drive base 28 and the cover 18 are connected by screws 18B, whichare inserted into holes 18A and 28C. The cover 18 is formed, by usingpressing techniques, with stepped portions 17A and 17C, and a groove17B. The groove 17B is fixed with a vibration absorption plate 10. Thestepped portions 17A and 17C prevent the heads of the screws fromprotruding, thus making the upper surface of the cover flat.Additionally, an enclosing seal 11 is applied to the overall surface ofthe cover. For the storage media, multiple magnetic disks 12 are mountedon a spindle motor 13 at predetermined distances from each other. Athreaded hole 13B in a rotational center of the spindle motor 13 engagesthe threaded hole 18A of the cover, resulting in heightened rigidity andvibration resistance.

[0044] The head slider 16 has a head for accessing the disk information,and this head is mounted at the end of a suspension 3, which is held byan actuator arm 15. A voice coil motor 14 composed of a coil part and amagnetic circuit furnished at the actuator arm 15 is arranged in thebase of the disk device. Thus, the head slider 16 is moved andcontrolled about a rotation shaft 15A (in the radial direction of thedisk 12) by the voice coil motor 13 driving the actuator arm 15. Therotation shaft 15A of the actuator arm 15 is formed with a threadedhole, and if this hole is engaged with the threaded hole of the cover,the device's rigidity and vibration resistance are increased.

[0045] Signals read out by the head of the head slider 16 from the disk12, as well as signals written onto the disk, travel through a flexibleprint circuit sheet 27, and are processed by the head control circuit.These signals continue to travel to a connector used in an opening 24,and are led to a circuit substrate 19, which is mounted with anothersignal processing circuit and a host controller which functions as aninterface for exchanging signals with the host.

[0046]FIG. 3(A) and FIG. 3(B) show a head assembly of the firstembodiment of the present invention, where FIG. 3(A) is the entire bodyof the head assembly, while FIG. 3(B)is a partially enlarged viewthereof. The head assembly 30 is composed of a head slider 36 and asuspension 31. The suspension 31 is formed by press-punching one sheetof an SUS material and has an attaching surface 33 for attaching thesuspension 31 to the head arm of the disk device. An attaching hole 33Ais formed within the attaching surface 33. A spacer 33B is furnished bylaser spot welding to provide the attaching strength. In addition, thespacer 33B is formed with a caulking hole (not shown) in a positioncorresponding to the attaching hole 33A, and the suspension is fixed bycaulking to the head arm. The suspension 31 is formed with a smallR-bend (such as that formed about a roller) in the vicinity of thespacer 33B to impart elasticity for pressing the head slider 36 towardsthe disk surface. =Further, the suspension 31 is provided with a sliderattaching portion 35D for attaching the head slider 36 to an oppositeend of the suspension from the head arm attaching surface 33.

[0047] The slider attaching portion 35D extends in the longitudinaldirection of the head slider 36, and is, when press-formed, processed byR-bending to have a curved surface 35E (including a semicylindricalouter circumference) that extends in the longitudinal direction of thehead slider 36. Alternatively, instead of the C-shaped cross-sectionshown, O-shaped, U-shaped or V-shaped cross-sections are alsocontemplated for the curved surface 35E. The slider attaching portion35D is formed with a generally U-shaped opening 35 around its perimeter,and is supported by beams 35A, 35B, and 35C.

[0048] The securing surface 36T of the head slider 36 is a suspensionattaching surface, and forms a surface contact, and not a point contact,between the slider 36 and the suspension 31. That is, since the curvedsurface 35E extends in the longitudinal direction (i.e., the lengthdirections of both the slider and the suspension), it comes into contactwith the securing surface 36T of the head slider in a linear manner. Theslider 36 also includes a surface 36D, which is the surface that willface the disk when head assembly 30 is installed with in a disk device.For the sake of simplicity, surface 36D will be referred to as the“lower slider surface” in this embodiment, as well as in the otherembodiments. However, it should be noted that if the suspension 31 isinstalled below its associated disk, surface 36D will not actually bebelow the remainder of the slider surface 36, but the designation “lowerslider surface” will still be utilized.

[0049] The head slider 36 is firmly secured to the suspension 31 bymeans of an adhesive 32 coated fully or partially on the curved surface35E. In each of the embodiments described herein, high-adhesionadhesives such as infrared radiation hardened resin, heat hardenedresin, cemedine, etc., may be used in to affix the head slider to thesuspension.

[0050] A read/write element 36A is provided on the side surface of thehead slider 36 by means of thin film forming, for example, and theread/write element 36A includes a recording head section and a readinghead section. It is important that the read/write element 36A maintainsthe required distance from a recording film of the disk in order toprovide the necessary stability for recording and/or reading of signals.

[0051] The enlarged view of FIG. 3(B) shows in particular the presenceof torsion in the suspension 31. The curved surface 35E and the securedsurface 36T face each other when the head arm attaching surface 33 andthe lower slider surface 36D are parallel to each other. However, due tothe presence of torsion, the contact portion between the curved surface35E and the secured surface 36T may not be aligned with the center lineC of the curved surface 35E. This means that if the curved surface 35Eand the secured surface 36T are brought into contact when the head armattaching surface 33 and the lower slider surface 36D (which faces thedisk) are in a parallel relationship, only the curved surface 35Erotates in the direction of the arrow and becomes misaligned Thus in thepresent invention, because there is only torsion in the curved surface35E, the overall torsion stress of the suspension is lowered Therefore,even if the contact portion D is not aligned with the center line C ofthe curved surface 35E, there is no longer the problem that the headslider 36 is fixed to the suspension 31, such that it is rotated indirection “a” or direction “b” similar to FIG. 1(A), because the(now-twisted) curved surface 35E and the secured surface 36T of the headslider 36 are affixed together by adhesive 32, where the twisting ofcurved surface 35E results in allowing the necessary parallelrelationship of the head arm attaching surface 33 and the lower slidersurface 36D to be maintained. In the FIG. 3(B) example, the arrowindicating rotation of the curved surface 35E points in acounterclockwise direction. However, since the torsion rotationcharacteristic of the curved surface 35E may be different for eachsuspension, the arrow may point in a clockwise direction in othersuspensions. Also, the amount of rotation may also be varied in responseto the degree of torsion stress.

[0052] When no torsion is present in the suspension, the contact portionD between the curved surface 35E and the secured surface 36T is alignedwith the center line C of the curved surface 35E when the head armattaching surface 33 and the lower slider surface 36D are parallel toeach other. Thus, whether or not torsion is present, with the presentinvention, it is possible to arrange the head arm attaching surface 33and the lower slider surface 36D so that they are parallel.

[0053] If the planar surface of the head arm attaching surface 33 isdesigned such that the planar surface of the head arm attaching surface33 is parallel to the disk surface, it is possible for the lower slidersurface 36D to also be parallel to the disk surface. Accordingly, it isthen possible for the read/write element 36A to be maintained at apredetermined distance from the recording film. Thus, by applying such ahead assembly 30 to the disk device of FIG. 2, a constant floatingheight can be maintained from the radial inner part to the radial outerpart of the disk. It is therefore possible to improve the recording andreading efficiency, as well as the durability and the reliability, ofthe disk device by reducing the frequency of contacts between the headslider and the disk.

[0054] In a modification of the present embodiment shown in FIG. 3(C),the head slider 36′ may be formed with a curved depression 36B′, and thehead slider attaching portion 35D′ may be planar, so that the curveddepression faces the planar plate. After the curved depression 361′ andthe planar slider attaching portion 35D′ are affixed together by anadhesive, the torsion of the support plate can be moderated in a similarmanner as that described above. Of course, the surface of the headslider facing the disk and the arm attaching surface of the supportplate must be kept parallel. In this modification of the firstembodiment, the slider attaching portion 35D′ is generally more narrowthan its equivalent in FIGS. 3(A) and 3(B), so that it can be seatedwithin the curved portion 36B′ of the slider 36′.

[0055]FIG. 4(A) and FIG. 4(B) show a head assembly of a secondembodiment of the invention. FIG. 4(A) shows the entire body of the headassembly, and FIG. 4(B) shows a partially enlarged view.

[0056] The head assembly 40 is composed of a head slider 46 and asuspension 41, which are formed in a similar manner as those of thefirst embodiment. Other features of this second embodiment similar tothe first embodiment will not be described again. However, it should benoted that the index numbers of similar features have been increased byten (10). Thus, for example, head slider 36 of the first embodimentbecomes head slider 46 in the second embodiment.

[0057] One difference from the first embodiment is that the suspension41 of the second embodiment is provided with a different type of headslider attaching portion 45D. The slider attaching portion 45D is planarin the longitudinal direction of the head slider 46, and is, whenpress-formed, punched into a planar plate extending in the longitudinaldirection of the head slider 46. Similar to that of the firstembodiment, the slider attaching portion 45D is formed with a generallyU-shaped opening 45 around its perimeter, and is supported by beams 45A,45B, and 45C.

[0058] In this embodiment, the center part of the securing surface 46Ton the slider 46 includes curved surface 46B, which may be formed, forexample, by cutting into the Al₂O₃TiC substrate of the head slider 46.This curved surface 46B is preferably shaped like the outercircumference of a cylinder, and thus forms a semicylindricallyprojected wall extending in the longitudinal direction. Instead of theC-shaped curved surface (in cross-section) shown, O-shaped, U-shaped orV-shaped cross-sections are also contemplated.

[0059] Since the curved surface 46B extends in the longitudinaldirection, it comes into contact with the attaching portion 45D in alinear manner. Accordingly, the slider attaching portion 45D and thecurved surface 46B form a surface contact therebetween, and not a pointcontact. In this regard, the head slider 46 should be firmly secured tothe suspension 41 by means of an adhesive 42 coated fully (or at leastpartially) on the curved surface 46B and/or on the slider attachingportion 45D.

[0060] A read/write element 46A is provided on the side surface of thehead slider 46 by means of thin film formation, for example, and theread/write element 46A includes a recording head section and a readinghead section. As in the first embodiment, it is important for the stablerecording and/or reading of signals that the read/write element 46A ismaintained at the required distance from the recording film of the disk.

[0061] An enlarged view of FIG. 4(B) shows in particular the presence oftorsion in the suspension 41. The curved surface 46B and the attachingportion 45D face each other when the head arm attaching surface 43 andthe lower slider surface 46D are parallel to each other. However, due tothe presence of twisting, the contact portion D between the curvedsurface 46B and the slider attaching portion 45D is not aligned with thecenter line C of the curved surface 46B. This fact means that if thecurved surface 46B and the slider attaching portion 45D are brought intocontact when the head arm attaching surface 43 and the lower slidersurface 46D are in a parallel relationship, only the slider attachingportion 45D rotates in the direction of the arrow (following the arc ofthe curved surface 46B) and becomes misaligned. Because only the sliderattaching portion 45D is twisted, the overall twisting stress of thesuspension is reduced.

[0062] In the example shown in FIG. 4(B), the arrow indicating thetwisting direction of the slider attaching portion 45D points in aclockwise direction. However, since the twisting rotation characteristicof the curved surface 35E may be different for each suspension, thearrow may point in a counterclockwise direction in other suspensions.The rotating amount thereof may also be varied in response to the degreeof twisting stress. However, irrespective of the magnitude and directionof the twisting, and even if the contact portion D is not aligned withthe center line C of the curved surface 46B, there is no longer theproblem that the head slider 46 is fixed to the suspension 41 under thecondition that head slider 46 is rotated in direction “a” or direction“b” (as shown in FIGS. 1(A) and 1(B)) because the twisting of the sliderattaching portion 45D compensates for the misalignment between thecontact portion D and the center line C. When no twisting is present inthe suspension, the contact portion D between the curved surface 46B andthe slider attaching portion 45D is aligned with the center line C ofthe curved surface 46B, as long as the head arm attaching surface 43 andthe lower slider surface 46D are parallel to each other. Thus, with orwithout twisting, it is possible to make the head arm attaching surface43 and the lower slider surface 46D parallel. Similar benefits to thosedescribed with regard to the first embodiment are also realized withthis embodiment.

[0063]FIG. 5(A) and FIG. 5(B) show a head assembly of a third embodimentof the invention. FIG. 5(A) shows the entire body of the head assembly,and FIG. 5(B) shows a partially enlarged view.

[0064] The same suspension 31 as shown in FIGS. 3(A) and 3(B) is used inthe head assembly 50 of the third embodiment shown in FIGS. 5(A) and5(B). As suspension 31 in FIGS. 5(A) and 5(B) is the same as suspension31 in FIGS. 3(A) and 3(B), the same reference numerals will be used todescribe like parts. Once again, suspension 31 is furnished with a headarm attaching surface 33 designed so that it is parallel to the disksurface, an attaching hole 33A, a spacer 33B, and a slider attachingportion 35D, which includes semicylindrically curved surface 35E.

[0065] As in FIGS. 3(A) and 3(B), the slider attaching surface 35D herein FIGS. 5(A) and 5(B) is also formed with a generally U-shaped opening35 around its perimeter, and is supported by beams 35A, 35B, and 35C.The securing surface 56T (or suspension attaching surface) of the headslider 56 is different from those of FIGS. 3(A) and 3(B) and FIGS. 4(A)and 4(B). In this embodiment, the securing surface 56T includes a curvedsurface 56B, which may be formed, for example, by cutting away a portionof the Al₂O₃TiC substrate from the rectangular head slider 56. Thecurved surface 56B is preferably the circumference (i.e., the innercircumference of a cylinder) of the semicylindrically depressed grooveextending in the longitudinal direction. The curved surface 35E (whichis preferably the outer circumference of a cylinder) may be placedwithin the curved surface 56B of the depressed groove of the securingsurface 56T by making use of its elasticity to reduce its width bypressing its edges together lightly. It is then fitted within the curvedsurface 56B by releasing the pressing force on its edges. In thisembodiment, the radii of curvature of the curved surfaces 35E and 56Bare preferably set at the same value selected from range between, forexample, 5 and 50 mm.

[0066] Since the curved surface 35E and the curved surface 56Bpreferably have the same radius of curvature (if the processingprecision is high), both curved surfaces come into full contact, ornearly full contact, along their arcs. On the other hand, if theprocessing precision is not as high, at least two-point contact orlinear two-line contact occurs, since the curved surface 35E and thecurved surface 56B are shaped as, respectively, the outer and innercircumferences of a cylinder.

[0067] Of course, the suspension can adequately support the head sliderby engaging in either the two-point contact or the two-line contact. Butby providing full surface contact, as is the preferred case with thepresent embodiment, the supporting strength can be increased. Whetherthe full surface contact, the point contact of not less than two pointsor the line contact of not less than two lines is employed depends uponthe processing precision of the curved surfaces 35E and 56B, as well asthe engagement between them, and numerous options are available.However, since a larger contact area increases the adhesion surface sothat it can be better secured by the adhesive, the supporting strengthof the head slider and the suspension is improved by such a largercontact area. The head slider 36 can be firmly secured to the suspension31 by using an adhesive that is fully coated on the curved surface 56Bof the suspension 56. In addition to the features previously described,a read/write element 56A is also provided on the surface at the side ofthe head slider 56 by means of thin film forming techniques, as in theother embodiments.

[0068] The enlarged view of FIG. 5(B) shows in particular the presenceof torsion in the suspension 31. The curved surface 35E and the curvedsurface 56B face each other when the head arm attaching surface 33 andthe lower surface 56D are parallel. However, due to the presence oftorsion, the contact portion D between the curved surface 35E and thecurved surface 56B is not aligned with the center line C of the curvedsurface 35E. This means that if the curved surface 35E and the curvedsurface 56B are brought into contact when the head arm attaching surface33 and the surface 56D of the head slider 56 facing the disk maintain aparallel relationship, only the curved surface 35E rotates in thedirection of the arrow and becomes misaligned. With torsion primarilylimited to the curved surface 35E only, the overall torsion stress ofthe suspension is reduced.

[0069] As in the other embodiments, the degree and direction of thetwisting stress may vary from one suspension to another. However, evenif the contact portion D is not aligned with the center line C of thecurved surface 35E, since the head arm attaching surface 33 and thelower slider surface 56D are maintained in a parallel relationship toeach other, there is no longer the problem that the head slider 56 isfixed to the suspension 31 so that it is rotated in direction “a” ordirection “b”.

[0070] When no torsion is present in the suspension, the contact portionD between the curved surface 35E and the curved surface 56B is alignedwith the center line C of the curved surface 35E when the head armattaching surface 33 and the surface 56D of the head slider 56 facingthe disk are parallel.

[0071] For the above mentioned structure, FIG. 5(C) shows the floatingheight of the head slider in the direction of the radius of the disk.Data line 41′ shows the case of no torsion in the suspension, and showsthat it has a constant head slider floating height from the inner sideto the outer side of the disk, and that the head slider floats at thepredetermined designed value, irrespective of its position on the disk.Data line 42′ shows the case of employing the current embodiment, withtorsion present in the suspension, and it shows that the floating heightis constant from the inner to the outer sides of the disk. That is, fromthis graph which shows that data line 41′ coincides with data line 42′,it is apparent that any effects of torsion on the suspension does notaffect the floating height of the head slider of the present invention.It is therefore possible to have the lower slider surface 56D positionedparallel to the disk surface, and subsequently the read/write element56A can be maintained at a fixed distance from the recording film of thedisk. Thus, if such a disk assembly 50 is applied to the disk device ofFIG. 2, it is possible to maintain a constant head slider floatingheight above the disk at both the inner and outer sides thereof.Accordingly, the recording and reading efficiency, durability, andreliability of the disk device can be improved by decreasing thefrequency of contacts between the disk and the head slider.

[0072]FIG. 6(A) and FIG. 6(B) show a head assembly of a fourthembodiment of the invention. FIG. 6(A) shows the entire body of the headassembly, and FIG. 6(B) shows a partially enlarged view. In the headassembly 60 shown, the same head slider 56 as that shown in FIGS. 5(A)and 5(B) is used. The main difference between this embodiment and thethird embodiment is that here, this embodiment includes changes in theradius of curvature of the curved surfaces 56B and 65E, whereas in thethird embodiment, both curved surfaces had the same radius of curvature.FIGS. 6(A)-6(B) show an example in which the radius of curvature of thecurved surface 65E is made larger than that of the curved surface 56B.However, functionally, either of the radii of curvature may be made tobe larger than the other. In the present embodiment, the radius ofcurvature is preferably selected from the range between 5 and 50 mm,depending upon the size of the head slider.

[0073] Similar to the other embodiments, the suspension 61 is furnishedwith a head arm attaching surface 63 designed so that it is parallel tothe disk surface, an attaching hole 63A, a spacer 63B, and a sliderattaching portion 65D for attaching a head slider 56. The sliderattaching portion 65D extends in the longitudinal direction of the headslider 56, and is, when press-formed, processed by R-bending so that itcreates a semicylindrically curved surface 65E (i.e., a cylindricalouter circumference).

[0074] As in the other embodiments, the slider attaching portion 65D isformed with a generally U-shaped opening 65 around its perimeter, and itis supported with beams 65A, 65B and 65C. The secured surface 56T (i.e.,the suspension attaching surface) of the head slider 56 is differentfrom those of FIGS. 3(A)-3(B) and FIGS. 4(A)-4(B). The head slider 56 isformed such that its securing surface 56T includes a curved surface 56B,which is preferably formed by cutting into the A1203TiC substrate of therectangular head slider 46. The curved surface 56B is preferably shapedlike the inner circumference of a cylinder, and forms asemicylindrically depressed groove extending in the longitudinaldirection.

[0075] Thus, the curved surface 65E (which is shaped as the outercircumference of a cylinder) of the suspension 61 is inserted within thecurved surface 56B of the depressed groove of the secured surface 56T ofthe head slider 56 by making use of its elasticity to reduce its widthby pressing its edges together lightly. It is then fitted within thecurved surface 56B by releasing the pressing force on its edges. Sincethe curved surface 65E and the curved surface 56B have different radiiof curvature, both make at least two-point contact on both sides at theend points. Furthermore, since the curved surface 65E and the curvedsurface 56B are the outer and inner circumferences of a cylinder andextend in the longitudinal direction at almost a constant radius ofcurvature, they make linear two-line contact starting at two points onboth sides of the ends of the curved surfaces 65E and 56B. Of course,the suspension can adequately support the head slider by engaging intwo-point contact. However, by providing the two-line contact aspreferred in the present embodiment, the supporting strength can beincreased. Although not shown, if the curved surface 65E is furtherpushed into the curved surface 56B, the curved surface 65E can bebrought into contact with the center of the curved surface 56B, and thearea coming into contact can be enlarged by making three-point contactor three-line contact.

[0076] The head slider 56 can be firmly secured to the suspension 61 byfull or partial coatings of adhesive 62A, 62B on the curved surface 56B.The cross-sections of the curved surfaces 65E and 56B may be U-shaped orV-shaped, and need not be C-shaped as shown. If the suspension and thehead slider are U-shaped or V-shaped, or a combination thereof, and thesuspension and the head have the same opening angle, an exact engagementbetween these two components may be made, which may result in theelimination of the ability of the suspension to shift in order tomoderate torsion. However, if the opening angle of the suspension ismade larger than that of the head slider, the same effect as thisembodiment can be provided.

[0077] In addition to the other features described, a read/write element56A is also 14: provided on the side surface of the head slider 56 bymeans of, for example, a thin film forming technique. The read/writeelement 56A has a recording head section and a reading head section. Itis important for stable recording and/or reading of signals that theread/write element 56A maintains the required distance from therecording film of the disk.

[0078] The enlarged view of FIG. 6(B) shows in particular the presenceof torsion in the suspension 61. The curved surfaces 65E and 56B faceeach other when the head arm attaching surface 63 and the lower slidersurface 56D are parallel. However, due to the presence of twisting, thecontact portions D between the curved surface 65E and the curved surface56B is not aligned with the center line C of the curved surface 65E.This means that if the curved surface 65E and the curved surface 56B arebrought into contact when the head arm attaching surface 63 and thelower slider surface 56D are maintained in a parallel relationship, onlythe curved surface 65E rotates in the direction of the arrow and becomesmisaligned. Because substantially only the curved surface 65E istwisted, the overall twisting stress of the suspension is reduced. As inthe other embodiments, the degree and direction of twisting may varyfrom one suspension to another. However, with the present invention, itis possible to use the curved surfaces 65E to mitigate the effects ofthe twisting, and subsequently the read/write element 56A can bemaintained at a fixed distance from the recording film of the disk.

[0079] Thus, if such a disk assembly 60 is utilized in the disk deviceof FIG. 2, it is possible to maintain a constant head slider floatingheight above both the radial inner and the radial outer sides of thedisk. Accordingly, the recording and reading efficiency, durability, andreliability of the disk device may be improved by decreasing thefrequency of contacts between the head slider and the disk.

[0080]FIG. 7(A) and FIG. 7(B) show a head assembly of a fifth embodimentof the invention. FIG. 7(A) shows the entire body of the head assembly,and FIG. 7(B) shows a partially enlarged view. In this embodiment, thesame head slider (slider 46) shown in FIGS. 4(A) and 4(B) is used inhead assembly 70, with like numbers designating like parts. Similar tothe suspension of the other embodiments, the suspension 71 of thisembodiment is furnished with a head arm attaching surface 73 designed sothat it is parallel to the disk surface, an attaching hole 73A, a spacer73B and a slider attaching portion 75D.

[0081] The slider attaching portion 75D extends in the longitudinaldirection of the head slider 46, and is, when press-formed, processed byR-bending so that it includes a semicylindrically curved surface 75Egenerally shaped as a cylindrical outer circumference. The sliderattaching portion 75D is formed with a generally U-shaped opening 75around its perimeter, and is supported by beams 75A, 75B and 75C.

[0082] The secured surface 46T of the head slider 46 is formed with acurved surface 46B, preferably formed by cutting into the Al₂O₃TiCsubstrate of the rectangular head slider 46. This curved surface 46B isformed on the opposite surface from that which faces the disk, andcurved surface 46B may be formed along with any slider rails included onthe disk facing surface of the slider. The curved surface 46B isgenerally shaped as the outer circumference of a cylinder, and thuscreates a semicylindrically depressed groove extending in thelongitudinal direction. The curved surface 75E is generally shaped asthe inner circumference of the cylinder. In this embodiment, the radiusof curvature of the curved surfaces 75E and 46B are designed so thatthey are the same. The radius of curvature is preferably selected fromthe range of between 5 and 50 mm, depending upon the size of the headslider. Since the curved surface 75E and the curved surface 46B have thesame radius of curvature (if the processing precision is high) bothcurved surfaces come into full contact along their arcs.

[0083] If the processing precision is not as high, since the curvedsurface 75E and the curved surface 46B comprise the inner or outercircumferences of a cylinder, the curved surface 75E meets the curvedsurface 46B as an enclosure. Thus, at least two-point contact or atleast linear two-line contact is created between of the curved surface75E and the curved surface 46B. Of course, the suspension can supportthe head slider by engaging in two-point or two-line contact, but byproviding full surface contact as preferred in the present embodiment,the supporting strength can be further increased. Whether full surfacecontact, point contact of not less than two points or line contact ofnot less than two lines is employed depends upon the processingprecision of the curved surfaces 75E and 46B, as well as the engagementbetween them, and various other options. However, since a larger contactarea increases the adhesion surface being secured by the adhesive, thesupporting strength of the head slider and the suspension can beimproved by increasing the contact area. The head slider 46 can befirmly secured to the suspension 71 by the adhesive 72 by being coatedfully or partially on the curved surface 46B of the suspension 46. Inaddition to the other features, a read/write element 46A is alsoprovided on the surface at the side of the head slider 56, preferably bymeans of the thin film forming art.

[0084] An enlarged view of FIG. 7(B) shows in particular the presence oftorsion in the suspension 71. The curved surface 75E and the curvedsurface 46B face each other when the head arm attaching surface 73 andthe lower slider surface 46D are parallel. However, due to the presenceof torsion, the contacting portion D between the curved surface 75E andthe curved surface 46B may not be aligned with the center line C of thecurved surface 75E. This means that if the curved surfaces 75E and 46Bare brought into contact when the head arm attaching surface 73 and thelower slider surface 46D are maintained in a parallel relationship, onlythe curved surface 75E rotates in the direction of the arrow and becomesmisaligned. Thus, because the torsion is contained in the curved surface75E only, the overall torsion stress of the suspension is reduced. As inthe other embodiments, torsion stress of different directions andmagnitudes than that shown may also occur in different suspensions.

[0085] However, regardless of the magnitude and direction of the torsionstress, even if the contacting portion D is not aligned with the centerline C of the curved surface 75E, since the head arm attaching surface73 and the lower slider surface 46D are maintained in a parallelrelationship, there is no longer the problem that the head slider 46 isfixed to the suspension 71 such that it is rotated in direction “a” ordirection “b”.

[0086] When no torsion is present in the suspension, the contact portionD between the curved surface 75E and the secured surface 46B is alignedwith the center line C of the curved surface 75E when the head armattaching surface 73 and the lower slider surface 46D are parallel. Itis therefore possible for the lower slider surface 46D to be maintainedparallel to the disk surface, and subsequently for the read/writeelement 46A to be maintained at a fixed distance from the recording filmof the disk. Thus, by including assembly 70 in the disk device of FIG.2, a constant floating height may be maintained from the radial innerportion to the radial outer portion of the disk. It is thereforepossible to improve the recording and reading efficiency, durability,and reliability of the disk device by reducing the frequency of contactsbetween the head slider and the disk.

[0087]FIG. 8(A) and FIG. 8(B) show the head assembly of a sixthembodiment of the invention. FIG. 8(A) is the entire body of the headassembly, and FIG. 8(B) shows a partially enlarged view. In headassembly 80 of this embodiment, the same head slider 46 as shown inFIGS. 4(A) through 4(B) is used, and therefor a detailed explanation ofthe slider will be omitted.

[0088] One difference between this embodiment and the fifth embodimentis that in this embodiment the suspension 81 includes a curved surface85E with a radius of curvature that is different from that of the curvedsurface 46B. Functionally, either radius of curvature may be made largerthan the other one, and FIGS. 8(A) and 8(B) show an example in which theradius of curvature of the curved surface 45E is made larger than thatof the curved surface 85E. In the present embodiment, the radius ofcurvature is preferably selected from the range of between 5 and 50 mm,depending upon the size of the head slider.

[0089] As in the other embodiments, the suspension 81 is furnished witha head arm attaching surface 83 designed so that it is parallel to thedisk surface, an attaching hole 83A, a spacer 83B and a slider attachingportion 85D. The slider attaching portion 85D extends in thelongitudinal direction of the head slider 46, and is, when press-formed,processed by R-bending to form a semicylindrically curved surface 85,which is generally in the shape of a cylindrical outer circumference85E. The slider attaching portion 85D is formed with a generallyU-shaped opening 85 around its perimeter, and is supported by beams 85A,85B and 85C.

[0090] Since the curved surface 85E and the curved surface 46B havedifferent radius of curvature, there is at least two-point contact orlinear two-line contact between the curved surface 85E and the curvedsurface 46B. Of course, the suspension can support the head slider byengaging in two-point contact, but by providing two-line contact aspreferred in the present embodiment, the supporting strength can befurther increased. Although not shown in the drawing, if the curvedsurface 85E is further pushed onto the curved surface 46B, the curvedsurface 85E can be brought into contact with the center of the curvedsurface 46B, and the total contact area can be enlarged by makingthree-point contact or three-line contact.

[0091] The head slider 46 can be firmly secured to the suspension 81 byadhesive 82A, 82B which may be coated on both edges of the two partsbeing connected. A read/write element 46A is provided on the sidesurface of the head slider 46, preferably by means of a thin filmforming technique, and the read/write element 46A has a recording headsection and a reading head section. For stable recording and or readingof signals, the read/write element 46A must maintain the requireddistance from the recording film of the disk.

[0092] The enlarged view of FIG. 8(B) shows in particular the presenceof torsion in the suspension 81. The curved surface 85E and the curvedsurface 46B face each other when the head arm attaching surface 83 andthe lower slider surface 46D are parallel. However, due to the presenceof torsion, the contact portion D between the curved surface 85E and thecurved surface 46B is not aligned with the center line C of the curvedsurface 85E. This means that if the curved surface 85E and the curvedsurface 46B are brought into contact when the head arm attaching surface83 and the lower slider surface 46D are maintained in a parallelrelationship, only the curved surface 75E rotates in the direction ofthe arrow and becomes misaligned. Thus, with the torsion being primarilylimited to the curved surface 85E only, the overall torsion of thesuspension is reduced. As in the other embodiments, the magnitude anddirection of the torsion stress may vary in different suspension units.However, as also with the other embodiments, the same problem related tomisaligned sliders is solved, resulting in the same benefits discussedearlier.

[0093] The cross sections of the curved surfaces 85E and 46B may beU-shaped or V-shaped, and need not be C-shaped, as shown in theembodiment of FIGS. 8(A) through 8(B). If the suspension and the headslider are U-shaped or V-shaped, or a combination thereof, and thesuspension and the head have the same opening angle, exact engagement ismade between them and the suspension is not moved for moderatingtorsion. However, if the opening angle of the suspension is made largerthan that of the head slider, the same effect as this embodiment can beachieved.

[0094]FIG. 9(A) and FIG. 9(B) show the head assembly of a seventhembodiment of the invention. FIG. 9(A) shows the entire body of the headassembly, and FIG. 9(B) shows a partially enlarged view. In thisembodiment, the same suspension as that shown in FIGS. 7(A) and 7(B)(and designated as suspension 71) has been designated as suspension in ahead assembly 90 in this embodiment. The suspension 91 is furnished witha head arm attaching surface 93 designed so that it is parallel to thedisk surface, an attaching hole 93A, a spacer 93B, and a sliderattaching portion 95D at an opposite side for attaching a head slider66.

[0095] The slider attaching portion 95D is shaped so that it extends inthe longitudinal direction of the head slider 66, and is, whenpress-formed, processed by R-bending so that it includes a curvedsurface 95E (shaped as the inner circumference of cylinder), which formsa semicylindrically depressed groove extending in the longitudinaldirection. The slider attaching portion 95D is formed with a generallyU-shaped opening 95 around its perimeter, and is supported by beams 95A,95B and 95C.

[0096] One important feature of this embodiment is that the securingsurface 66T of the head slider 66 is formed with a step 66F at one endthereof that is higher than the curved surface 66B. This step 66F servesas a positioning side wall to position the slider attaching portion 95D.The curved surface 66B is preferably shaped as the outer circumferenceof the cylinder, or as the outer circumference of a semicolumn. Thecurved surface 95E is generally shaped as inner circumference of acylinder.

[0097] Similar to the embodiment shown in FIGS. 7(A) and 7(B), thecurved surfaces 95E and 66B are designed to have the same radius ofcurvature, but if varied as in the embodiment of FIGS. 8(A) and 8(B),the function is the same. In the present embodiment, the radius ofcurvature is preferably selected from the range of between 5 and 50 mm,depending upon the size of the head slider. If the curved surface 95Eand the curved surface 66B have the same radius of curvature (if theprocessing precision is high), both curved surfaces come into fullcontact along their arcs. If the processing precision is not as high, orif both radii of curvature are intended to be different as in theembodiment of FIGS. 8(A)-8(B), the curved surface 95E meets the curvedsurface 66B by enclosing it, and there is at least two-point contact orlinear two-line contact between these two parts. Of course, thesuspension can support the head slider by engaging in either two-pointcontact or two-line contact, but by providing full surface contact aspreferred in the present embodiment, the supporting strength can befurther increased. Whether the full surface contact, the point contactof not less than two points, or the line contact of not less than twolines is employed depends on the processing precision of the curvedsurface 95E and the curved surface 66B, and the engagement between them,and various options are available. However, since a larger contact areaincreases the adhesion surface secured by the adhesive, the supportingstrength of the head slider and the suspension may be improved byincreasing the contact area.

[0098] The head slider 66 can be firmly secured to the suspension 91 byadhesive 92 which is coated fully or partially on the curved surface 66Bof the suspension 96. In the current embodiment, in addition to theeffect of the suspension on torsion similar to that found in thesuspensions shown in FIGS. 7(A)-7(B) and 8(A)-8(B), it is also possibleto improve the positioning precision in the longitudinal direction(backwards and forwards) of the head slider 66 of the slider attachingsurface 95D by providing a positioning wall surface such as the step66F. With such a positioning wall surface, is therefore easy to massproduce suspension assemblies with the head slider mounted uniformly onthe suspension. Accordingly, if suspensions of uniform precision areemployed in the disk device shown in FIG. 2, it is possible to enhancethe precision and the reliability of the disk device.

[0099]FIG. 10(A) and FIG. 10(B) show the head assembly of an eighthembodiment of the invention. FIG. 10(A) shows the entire body of thehead assembly, and FIG. 10(B) shows a partially enlarged view. In thisembodiment, the same suspension (designated as suspension 31) as shownin FIGS. 5(A) and 5(B) is used here and has been designated assuspension 101 in head assembly 100. The suspension 101 is furnishedwith a head arm attaching surface 103 designed so that it is parallel tothe disk surface, an attaching hole 93A, a spacer 93B, and a sliderattaching portion 105D. The slider attaching portion 105D is shaped toextend in the longitudinal direction of the head slider 76, and is, whenpress-formed, processed by R-bending so that it includes a curvedsurface 105E (generally shaped as the outer circumference of thecylinder), which is the of the semicylinder extending in thelongitudinal direction of the head slider 76. The slider attachingportion 105D is formed with a generally U-shaped opening 105 around itsperimeter, and is supported by three beams 105A, 105B and 105C. Inaddition to the curved surface 76B of the depressed groove formed bycutting a semicylinder into the slider (similar to that of theembodiment of FIGS. 5(A)-5(B)), the securing surface (the suspensionattaching surface) 76T of this embodiment is also provided with apositioning wall surface 76F, located where the curved surface 105Fstrikes against the end of the curved surface 76B. The curved surface105E of the suspension 101 is placed within the curved surface 76B ofthe depressed groove of the secured surface 76T of the head slider 76 bymaking use of its elasticity to reduce its width by pressing lightly. Itis then fitted within the curved surface 76B by releasing the pressingforce on its edges.

[0100] Similar to the embodiment of FIGS. 5(A) and 5(B), the curvedsurfaces 105E and 76B are designed to have the same radius of curvature.However, it is also contemplated that each radii may be different as inthe embodiment of FIGS. 6(A) and 6(B). In the present embodiment, theradius of curvature is preferably selected from the range of between 5and 50 mm, depending upon the size of the head slider. Since the curvedsurface 105E and the curved surface 76B have the same radius ofcurvature, if the processing precision is high, both curved surfacescome into full contact along their arcs. On the other hand, if theprocessing precision is not too high, or if both radii of curvature areintended to be different as in the embodiment FIGS. 6(A) and 6(B), thecurved surface 105E may make at least two-point contact or lineartwo-line contact. Of course, the suspension can support the head sliderby engaging in either two-point contact or two-line contact, but byproviding full surface contact as preferred in the present embodiment,the supporting strength can be further increased. Whether full surfacecontact, point contact of not less than two points, or line contact ofnot less than two lines is employed depends on the processing precisionof the curved surface 105E and the curved surface 76B, and theengagement between them, and various options are available. However,since a larger contact area increases the adhesion surface so that itcan be secured by the adhesive, the supporting strength of the headslider and the suspension are improved with an increase in the centralarea.

[0101] The head slider 76 can be firmly secured to the suspension 101 byan adhesive coated fully or partially on the curved surface 76B of thesuspension 76. The adhesive may also be coated upon the curved surface105E of the slider, either in addition to the adhesive coated upon thesuspension 76 or instead of that adhesive. In the current embodiment, inaddition to mitigating the effects of torsion as in the embodiments ofFIGS. 5(A), and 5(B) and 6(A) and 6(B), it is also possible to improvethe positioning precision in the longitudinal direction of the headslider 76 providing the positioning wall surface 76F. It is thereforeeasy to mass produce suspension assemblies with the head sliders mounteduniformly on the suspension. Accordingly, if a suspension of uniformprecision is employed in the disk device of FIG. 2, it is possible toenhance the precision and reliability of the disk device.

[0102] The assembly which utilizes the head assemblies of embodiments 1to 8 and the technology of this invention may also employ a suspensionin which signal wiring for exchanging signals with the head elementparts of the head slider is patterned by utilizing thin film formingtechnique (spattering, vacuum vaporization, plasma CVD etc.). The wirepattern is formed on the surface of the suspension on the side where thehead slider is mounted, and extends along the beams of the suspension inthe vicinity of the head slider mounting portion. The wire pattern ispositioned such that the terminal of the wire pattern vertically facesthe terminal of the head element. The terminals of the wiring patternand of the head element are preferably connected by a ball bondingtechnique in which materials with good heat conductivity (such as goldor copper) are shaped into balls and brought into surface contact withthe terminals of both the wire pattern and the head element. Theterminal surface of the suspension is preferably formed so that it isflat with no curved surfaces, depressions, or protrusions, to facilitatethe ball bonding process. The terminal of the head slider is alsopreferably formed at a position that lacks projections or depressions toalso facilitate ball process. If the curvature or opening angle of theprojection or depression is made large, the ball bonding can be easilydone.

[0103] FIGS. 11(A) to (D) show a first embodiment of a procedure forassembling the suspension and the head slider together. As shown in FIG.11(A), suspension 203 is held by a suspension holding arm 202 such thatthe arm attaching portion is parallel to a disk or other planar surface205. First, the head slider 204 is placed on a service plate of thedisk/planar surface 205. Before the head slider 204 is placed upon thedisk/planar surface 205, the left/right alignment of the suspension andhead slider are determined so that the slider is properly centered withrespect to the sides of the suspension.

[0104] When the suspension holding arm 202 moves down (as shown by thearrow in FIG. 11(A)), the suspension 203 is brought closer to the headslider 204. In FIG. 11(B), the height of the suspension 203 is adjustedwith respect to the head slider 204. This procedure requires carefulattention so that the suspension 203 does not strike against the headslider 204 with too much force, causing deformation due to itselasticity. During this step, the arm is moved up or down until apredetermined mounting height has been reached. In FIG. 11(C), thelongitudinal position of the suspension 203 with respect to the headslider 204 is adjusted. The slider attaching surface of the suspensionfaces the suspension attaching surface of the head slider. After thesuspension 203 and the head slider 204 have been properly positioned,the adhesive is applied between the two components, as shown by thearrow in FIG. 11(D).

[0105] By positioning the suspension and the head slider as described,the arm attaching surface of the suspension and the lower slider surfacemay be maintained in a parallel relationship. If the suspension and thehead slider are secured with an adhesive while maintaining the aboveparallel condition, the arm attaching surface of the suspension and thelower slider surface will be maintained in the desired parallelcondition. The assembled head slider and suspension combination may thusbe mounted into a disk device, such as that shown in FIG. 2.

[0106] In the example attachment procedure shown in FIGS. 11(A) through11(D), the suspensions are attached one by one. However, it is alsopossible to attach multiple suspensions and multiple head sliderstogether at the same time when the suspensions are held together in apress sheet. After assembly, the suspensions are separated from thepress sheet. Thus, many head sliders can be adhered to the suspensionsat the same time, and the production efficiency of the head assembly isincreased.

[0107] FIGS. 12(A) through (12E) show a second embodiment procedure forassembling the suspension and the head slider together. This embodimentshows the adhesion of suspensions 213A through 213F to a series of headsliders. As shown in FIG. 12(A), multiple suspensions 213A through 213Fare attached to multiple arms 212A through 212C, whereby each armsupports two suspensions. The arms 212A through 212C are mounted oncarriage 211. As shown in FIG. 12(B), when multiple suspensions 213Athrough 213F are moved onto their associated head sliders, the opposedsurfaces of each pair of suspensions (213A/213B, 213C/213D, 213E/213F)are held by vacuum nozzles 215A through 215C so they do not touch thehead slider and service plate. FIG. 12(C) shows head sliders 216A and216B placed on service plates 216 to face respectively, suspensions 213Aand 213B. The head sliders 216A and 216B are firmly held on theirassociated service plate 216 by means of a set of holders 217. In FIG.12(D), the service plate 216 is moved to carry out positioning in thelongitudinal direction of the suspensions, as well as in the right andleft directions. Once the sliders are properly positioned, the vacuumnozzles 215A and 215B are released, and the head sliders 216A and 216Bare mounted onto the suspensions 213A and 213B. As shown in FIG. 12(E),nozzles 219A and 219B are used to apply an adhesive 218 onto theconnecting parts of the head slider and the suspension. Once each headslider is secured to its associated suspension, holders 217 are removed,and the service plates 216 are withdrawn. The same procedure is appliedto the other suspensions 213C through 213F. By positioning thesuspension and the head slider in this manner, the arm attaching surfaceof the suspension and the lower slider surface may be kept parallel toeach other.

[0108] If the suspension and the head slider are secured together by anadhesive while maintaining the above conditions, the arm attachingsurface of the suspension and the lower slider surface will be attachedso that they are parallel. Further, when mounting the suspensionassembly into a disk device, high-precision parallelism can be achieved.Thus, it is possible to prevent biasing of the head slider whenattaching the head slider, and also to avoid fluctuations in thefloating height of head slider. Further, in this embodiment, multiplehead sliders can be attached at once, and the assembly time can beshortened.

[0109] FIGS. 13(A) through 13(E) show a third embodiment of a procedurefor assembling the suspension and the head slider together. In thisembodiment, the head slider is being adhered to the suspension whilepositioned in a disk device that includes an arm and at least one disk.FIG. 13(A) shows the suspension 233 as being attached to the arm 232.The arm 233 is mounted on a carriage 231 adapted for rotating anddriving the arm. The head slider 236 is mounted on the disk 230 by meansof the holder 234. FIG. 13(B) shows, in cross-section, the head sliders236A and 236B being held on the disks 230A and 230B by means of holders236A and 236B. FIG. 13(C) shows, in cross-section, suspensions 233A and233B being moved onto the head slider with the facing surfaces of thesuspensions being held by a vacuum nozzle 235. The vacuum nozzle 235 ispositioned between the two suspensions attached to the same arm. In FIG.13(D), the arm 232 is rotated to align the suspension 233 with the headslider 236 in the radial direction. At this point, the head slider 236is still mounted on the disk 230. FIG. 13(E) shows, in cross-section,the head sliders 236A and 236B mounted on the suspensions 233A and 233Bthrough use of the vacuum nozzle 235 (shown in FIG. 13(C)). Adhesivenozzles 239A and 239B are used to apply adhesive 238 to the connectionof the head slider and the suspension to secure them together. This sameprocedure is used for other suspensions. By positioning the suspensionand the head slider in this manner, the arm attaching surface of thesuspension lower slider surface may be kept parallel to each other.

[0110] If the suspension and the head slider are secured together withthe adhesive while maintaining the above conditions, the arm attachingsurface of the suspension and the lower slider surface will be attachedso that they are parallel. If the head slider is adhered while thesuspension is secured to the arm of a disk device, a high-precisionsurface parallel relationship can be achieved. Thus, with this assemblyprocedure, it is possible to prevent inclining the head slider whileattaching the head slider to the suspension and to avoid fluctuations inthe floating height of the head slider. Further, in this embodiment, theattachment of multiple head sliders at once is possible, and thus theassembly time can be shortened.

[0111] FIGS. 14(A) through 14(E) show a fourth embodiment of a procedurefor assembling the suspension and the head slider together. Thisembodiment also shows that the head slider can be adhered to thesuspension while mounted in a disk device. The present embodiment showsthe attachment of multiple head sliders to multiple suspensions 223Athrough 223F.

[0112] In FIG. 14(A), multiple suspensions 223A through 223F areattached to arms 222A through 222C, such that each arm supports twosuspensions. The arms 222A through 222C are mounted on a carriage 221.In FIG. 14(B), the head sliders 226A and 226B are held in the grooves ofthe service plates 224A and 224B. The service plates 224A and 224B areprovided with slopes 225A and 225B. When the service plates 224A and224B move between the suspensions 223A and 223B, the suspension movesalong this slope and is lead to the position where the head slider ismounted. In FIG. 14(C), the suspensions 223A and 223B and the headsliders 226A and 226B have been positioned with respect to thesuspensions 223A and 223B so that they are properly aligned in both thelongitudinal direction, as well as in the left-right direction. In FIG.14(D), nozzles 229A and 229B are used to apply the adhesive 238 at theinterface between the head slider and the suspension to secure themtogether, so that and withdraw the service plates 224A and 224B can bewithdrawn. Other head sliders are adhered to the suspensions by usingthe same procedure. By positioning the suspension and the head slider inthis manner, the arm attaching surface of the suspension and the surfaceof the head slider facing the disk may be held parallel. Similarbenefits to those described with respect to the third embodimentattaching procedure can also be achieved with this fourth embodiment ofthe attaching procedure.

[0113] FIGS. 15(A)-(B) show a fifth embodiment of a procedure forattaching the suspension and the head slider together. This embodimentshows the head slider adhered to the suspension in a disk device with anarm and a disk.

[0114]FIG. 15(A) shows one of multiple suspensions 233 that are mountedto arm 232. The arm 232 is in turn mounted on a carriage 231 that isconfigured for driving the arms. Referring now to FIG. 15(B), a slope237 (shown in cross-section in FIGS. 16(A) through 16(B)) is shown asbeing provided near a holder 234. When the suspension 233 is rotatedtoward the center of disk 230 by the arm 232, the suspension 233 movesalong the slope 237, and is led to a position where the head slider 236is mounted upon the suspension 233. As in the embodiment of FIGS.14(A)-14(D), a nozzle is used to apply adhesive to the area ofconnection between the head slider and the suspension to secure themtogether, and the holder 234 and the slope 237 are withdrawn. Othersuspensions in the disk device are adhered to their associated headsliders by using this same procedure. By positioning the suspension andthe head slider in this manner, the arm attaching surface of thesuspension and the surface of the head slider facing the disk can beheld parallel. This embodiment also achieves the same benefits, such asthose related to maintaining a parallel relationship between the armattaching surfaces and lower the slider surfaces, as described inprevious embodiments.

[0115] FIGS. 16(A) through 16(E) show a sixth embodiment of a procedurefor attaching the suspension and the head slider together. Thisembodiment is essentially the same as the embodiment of FIGS. 15(A)through 15(B) except this embodiment also includes a shaker 241. FIGS.16(A) through 16(B) are essentially a cross-section of FIGS. 15(A)through 15(B), except for the shaker 241.

[0116] Referring back to FIGS. 16(A) through 16(B), the head slider 236is firmly held by the holder 234. The suspension attaching surface ofthe head slider 236 has a curved surface 236B (FIG. 16(B)) formed of adepressed groove in substantially the shape of the inner circumferenceof a cylinder. The slider attaching surface of the suspension 233 has acurved surface 235E shaped generally as the outer circumference ofcylinder. After the slider attaching surface moves along the slope 237,the curved surface 235E engages the curved surface 236B. If the frictionbetween the suspension and the head slider overcomes the torsionalrigidity of the suspension, the suspension will be twisted. If both thesuspension and the slider are adhered to each other in this twistedcondition, unwanted floating fluctuation occurs when the suspensionassembly is put to use in a disk drive.

[0117] In the present embodiment, to overcome the friction between theslider and the suspension, shaker 241 vibrates the area of connectionbetween the head slider and the suspension, preferably with a vibratorymotion parallel to the surface of the disk. The arrows in FIGS.16(A)-16(B) represent the suspension moving as it vibrates and rotates,with the curved surface 235E following the arc. By applying vibration,an air space is created between the suspension and the head slider tocancel out the friction between them, and by use of its spring stress(torsional rigidity), the head slider attaching surface of thesuspension can be returned to a stable torsion state. If the suspensionand the head slider are adhered under this condition, since the torsionis absorbed in the head slider attaching surface, it is possible tocancel out the effects of torsion on head slider and the arm attachingpart. If the vibration imparting technique of this embodiment is appliedto the attaching procedures of the other five embodiments, torsion canbe more effectively mitigated. This can also be applied to a variety ofcombinations of other shapes of suspensions and head sliders. It ispossible to increase the shaking frequency (to a frequency of, forexample, 8 KHz, and more effectively, to at least 10 KHz) of the shakerto a value higher than the resonant vibration of the suspension (of, forexample 5 KHz), and to apply the vibration perpendicular to theconnection between the head slider and the suspension. For controllingresonance of the suspension during shaking, the shaking frequency mustnot be an integer multiple of the resonant frequency of the suspension.If the technology of the above shown attaching procedures of embodimentsone through six are employed, the head assemblies of the technologyshown in embodiments one through eight can be made, and any residualtorsion during adhesion can be removed. Further, it is possible toarrange the arm attaching surface of the support plate in parallel tothe surface of the head slider facing the disk by means of a simpleassembly structure, or by mounting them onto the actual disk device.Thus, the present invention can be expected to enhance the attachingprecision of the head slider and to stabilize the floatingcharacteristics of the head slider.

[0118] In summary with the present invention, it is possible to arrangethe surface of the head slider facing the disk to be parallel to thedisk surface, and as a result, the read/write element will be held at apredetermined distance from the recording film of the disk. Thus, thefloating height of the head slider can be held at a constant distancefrom both the inner and outer sides of the disk. Accordingly, it ispossible to enhance the recording and reading efficiency, durability,and reliability of the disk device by reducing the frequency of contactbetween the head slider and the disk.

[0119] While various embodiments of the present invention have beenshown and described, it should be understood that other modification,substitutions and alternatives may be apparent to one of ordinary skillin the art. Such modifications, substitutions and alternatives can bemade from the appended claims. Various features of the invention are setforth in the appended claims.

What is claimed is:
 1. A head assembly comprising: a head slider with aread/write element for reading/recording information to/from a disk; asuspension for supporting the head slider, said suspension including agenerally planar sheet that extends in a longitudinal direction from afirst end to second end; an arm attaching portion located near saidfirst end of said generally planar sheet of said suspension, said armattaching portion being adapted to be attached to a head arm; and aslider attaching portion positioned near said second end of saidgenerally planar sheet of said suspension, said slider attaching portionextending generally in said longitudinal direction and being surroundedby a generally U-shaped opening in said generally planar sheet, saidslider attaching portion facing a securing surface of said head slider;wherein at least one of said slider attaching portion of said suspensionand said securing surface of said head slider includes a nonplanarportion, and further wherein said head slider and said suspension areaffixed to each other at said nonplanar portion, whereby the effects oftorsion upon the alignment of said head slider are mitigated by saidnonplanar portion.
 2. The head assembly defined in claim 1 , whereinsaid nonplanar portion is curved along said longitudinal direction. 3.The head assembly defined in claim 1 , wherein said nonplanar portion islocated on said slider attaching portion of said suspension.
 4. The headassembly defined in claim 3 , wherein said securing surface of said headslider is generally planar in the vicinity where said slider attachingportion of said suspension is affixed thereto.
 5. The head assemblydefined in claim 3 , wherein said nonplanar portion of said sliderattaching portion is curved along said longitudinal direction to definea convex surface that faces said securing surface of said head slider.6. The head assembly defined in claim 5 , wherein said securing surfaceof said head slider includes a second nonplanar portion curved alongsaid longitudinal direction to define a concave surface thereon forseating said convex surface of slider attaching portion of saidsuspension.
 7. The head assembly defined in claim 6 , wherein saidconvex surface and said concave surface are both of approximately thesame radius of curvature.
 8. The head assembly defined in claim 6 ,wherein the radius of curvature of said convex surface is greater thanthe radius of curvature of said concave surface.
 9. The head assemblydefined in claim 6 , wherein the radius of curvature of said concavesurface is greater than the radius of curvature of said convex surface.10. The head assembly defined in claim 5 , further comprising apositioning wall located at one end of said securing surface of saidhead slider, wherein said positioning wall aids in the positioning ofthe slider attaching portion upon the securing surface of the headslider by providing a surface for an end of said slider attachingportion to abut against during assembly.
 11. The head assembly definedin claim 3 , wherein said nonplanar portion of said slider attachingportion is curved along said longitudinal direction to define a concavesurface that faces said securing surface of said head slider.
 12. Thehead assembly defined in claim 11 , wherein said securing surface ofsaid head slider includes a second nonplanar portion curved along saidlongitudinal direction to define a convex surface thereon for seatingsaid concave surface of slider attaching portion of said suspension. 13.The head assembly defined in claim 12 , wherein said convex surface andsaid concave surface are both of approximately the same radius ofcurvature.
 14. The head assembly defined in claim 11 , wherein theradius of curvature of said convex surface is greater than the radius ofcurvature of said concave surface.
 15. The head assembly defined inclaim 11 , wherein the radius of curvature of said concave surface isgreater than the radius of curvature of said convex surface.
 16. Thehead assembly defined in claim 11 , further comprising a stepped portionlocated at one end of said securing surface of said head slider, whereinsaid stepped portion aids in the positioning of the slider attachingportion upon the securing surface of the head slider by providing asurface for an end of said slider attaching portion to abut againstduring assembly.
 17. The head assembly defined in claim 1 , where insaid nonplanar portion is located on said securing surface of said headslider.
 18. The head assembly defined in claim 17 , wherein saidnonplanar portion of said securing surface of said head slider is curvedalong said longitudinal direction to define a convex surface that facessaid slider attaching portion of said suspension.
 19. The head assemblydefined in claim 17 , wherein said slider attaching portion of saidsuspension is generally planar in the vicinity where said securingsurface of said head slider is affixed thereto.
 20. The head assemblydefined in claim 1 , wherein said slider attaching portion of saidsuspension and said securing surface of said head slider each include anonplanar portion, and whereby each nonplanar portion is curved alongsaid longitudinal direction.
 21. The head assembly defined in claim 1 ,further comprising a second nonplanar portion on the other of saidslider attaching portion and said securing surface, wherein said sliderattaching portion and said securing surface contact each other along atleast two lines thereon.
 22. The head slider assembly defined in claim 1, wherein said suspension further includes an arm attaching surface forattaching said suspension to an arm of a disk device, and furtherwherein said head slider includes a lower surface that faces in anopposite direction from said securing surface, such that said armattaching surface of said suspension and said lower surface of said headslider are maintained in a generally parallel relationship to eachother.
 23. A suspension for use in supporting a head slider in aninformation storage device, said suspension comprising: a generallyplanar sheet that extends in a longitudinal direction from a first endto second end; an arm attaching portion located near said first end ofsaid generally planar sheet, said attaching portion being adapted to beattached to a head arm; and a slider attaching portion positioned nearsaid second end of said generally planar sheet, said slider attachingportion extending generally in said longitudinal direction and beingsurrounded by a generally U-shaped opening in said generally planarsheet, said slider attaching portion being curved along at least aportion of the longitudinal length thereof.
 24. The suspension definedin claim 23 , wherein said curved portion of said slider attachingportion defines a convex surface on one side thereof and a concavesurface on an opposite side thereof.
 25. The suspension defined in claim24 , wherein said concave surface is a surface that is adapted tosupport a head slider.
 26. The suspension defined in claim 24 , whereinsaid convex surface is a surface that is adapted to support a headslider.
 27. The suspension defined in claim 24 , wherein said curvedportion of said slider attaching portion includes a generally arcuatecross-section, with a central axis thereof that extends generally insaid longitudinal direction.
 28. An information storage devicecomprising: a storage media for storing information; a head slider witha read/write element for reading/recording information to/from saidstorage media; a suspension for supporting the head slider, saidsuspension including a generally planar sheet that extends in alongitudinal direction from a first end to second end; an arm attachingportion located near said first end of said generally planar sheet ofsaid suspension, said arm attaching portion being adapted to be attachedto a head arm; a slider attaching portion positioned near said secondend of said generally planar sheet of said suspension, said sliderattaching portion extending generally in said longitudinal direction andbeing surrounded by a generally U-shaped opening in said generallyplanar sheet, said slider attaching portion facing a securing surface ofsaid head slider; wherein at least one of said slider attaching portionof said suspension and said securing surface of said head sliderincludes a curved portion, and further wherein said head slider and saidsuspension are affixed to each other at said curved portion, whereby theeffects of torsion upon the alignment of said head slider are mitigatedby said curved portion; a head arm for supporting said suspension,whereby said first end of said suspension is attached to a free end ofsaid head arm; and a motor for moving said head arm to enable said headslider to access different areas of said storage media.
 29. Theinformation storage device defined in claim 28 , wherein said suspensionfurther includes an arm attaching surface for attaching said suspensionto said head arm, and further wherein said head slider includes a lowersurface that faces in an opposite direction from said securing surface,such that said arm attaching surface of said suspension and said lowersurface of said head slider are maintained in a generally parallelrelationship to each other.
 30. The information storage device definedin claim 28 , wherein said curved surface is located upon said sliderattaching portion of said suspension.
 31. The information storage devicedefined in claim 28 , wherein said curved surface is located upon saidsecuring surface of said head slider.
 32. The information storage devicedefined in claim 28 , wherein said curved surface is located upon saidslider attaching portion of said suspension and further wherein a secondcurved surface is located upon said securing surface of said headslider.